Transfer one audio file (example: snare of a conductor's drum line score) to Garageband

I'm a 4t/5th grade private school music instructor. We're presently working with our drum lines. I've created a conductor's score of 4 parts (snare, toms, bass drum, cymbals). When I export the song, even if I've clicked "solo" on one of the parts, it still transfers the entire conductor's score to the mp3. Is there a way to have it export each of the 4 parts, individually as an mp3 so I can create demo mp3s for the students?